Study Of Preparation And Properties Of Core-sheath Bicomponent Wig Fibers With Phase Change Materials

In recent years, chinese hair products are going into an rapid development period. Synthetic wig fibers aren't subject to resource limit,and change color, a great variety of design according to market, and own high added-value, and therefore become the mainstream of hair products. From a global point of view, hair products are mainly used for decoration, special need works(lawyers, actors or actresses), teaching (beauty salon industry), and compensation for defects. Hair products are more as "fashion of head" for "Dressing". With the continuous improvement of living standards, comfortable and functional hair products are favored much better. Development of wig fibers cool in summer and warm in winter would benefit consumers wearing wigs in different seasons.Phase change material octadecane (C18H38) is used in this study with phase transition temperature of 25-32℃(phase transition temperature range is similar to the temperature range of human body). Octadecane is a kind of low molecular weight and poor mechanical property materials, and the core of core-sheath bicomponent wig fibers are EVA30/30/octadecane blends. Therefore, EVA30/30 is added into octadecane to improve its mechanical property, processing behavior, thermal property, package effect and lasting stability. The EVA30/30 network-like structure becomes loose because of the clash of octadecane and network-like structure. It is found that the more the content of octadecane is, the looser the network-like structure of EVA30/30 becomes:during non-isothermal process, the grain growth in EVA30/3o/octadecane blends is blocked and the crystallization ability of the system further declines; the tensile strength and elongation at break of EVA3o/3o/octadecane blend membrane decline; leaking test of EVA3o/3o/octadecane blend membrane indicates that leakage is more obvious, when octadecane is <55wt%, the mass loss rate increases very slowly with the increase of sampling time. When octadecane is≥60wt%, however, the mass loss rate increases obviously with the increase of sampling time. Therefore, the appropriate amount of core for core-sheath bicomponent wig fibers are EVA30/30/octadecane blends with 55wt% octadecane. Octadecane in the core is low-temperature phase change material with low melting point and decomposition temperature, so the sheath materials must have a low melt spinning temperature to prevent phase change material from decomposing in the spinning process. The sheath are EVA28/150/HDPE blends with EVA28/150 as based raw materials, the reasons are listed as follows: first, the spinning temperature is low enough; second, a lot of EVA28/150 and EVA30/30 having good compatibility with each other are obtained in the sheath and core respectively, so the sheath and core are not easy to fall off during the application. HDPE in the sheath can increase the strength of blend fibers and match to the low melting point of EVA28/150.It's found that when the HDPE content of blends is about 15%, the spinnability of blends and the mechanical property of blend fibers are the best. Therefore, the composition for sheath of core-sheath bicomponent wig fibers is EVA28/150/HDPE blends with 15% HDPE.Bicomponent melt spinning machine is used in this study. FTIR shows that octadecane has been packed into core-sheath bicomponent wig fibers; draw temperature is 50℃, draw ratios are 2.5,3,3.5 and 4 respectively. The result shows that with the increase of draw ratio, the tensile strength of bicomponent fibers increases and elongation at break decreases; the tensile strength and elongation at break decrease with the increase of core content; when the given elongation is≤75% and the given load is≤40cN, whether it is stretched one time or five times, the core-sheath bicomponent wig fibers have good elastic recovery; with the increase of core content equivalent to the increase of octadecane, the fiber elastic recovery decreases; the phase change material will not leak out from the core-sheath bicomponent wig fibers; the content of phase change material in the fibers measured by DSC meets that of theoretical calculation; the core-sheath bicomponent wig fibers show good freeze-thaw cycle stability after experiencing 50 freeze-thaw cycles.